Your client does NOT HAVE TO GO TO a rehab centre for your average FHO patient to be successful. They can do the work at home under your tutelage and have a very good outcome.
It is true that the patient might have a more complete and faster recovery at a certified rehabilitation [centre], but the pets of dedicated owners can and will also achieve a successful outcome.
I would strongly recommend that your more difficult cases (chronic hip pathology patient with much existing fibrous tissue) do go to a rehabilitation centre however, as the additional modalities, expertise and attention to detail will make a big difference.
Either way (at home or in a rehab centre), the pet owner needs to put in the time and do the work.